Hi all, longtime Teensy fan here and first time poster. After 3+ years of Teensy-related triumphs it appears I've just fried a few Teensy 3.2s for reasons which are beyond me, and I was hoping some folks here might offer their thoughts.
I have a circuit in which a Teensy 3.2 is controlling a motor driver and a few simple digital and analog I/Os (just a few buttons and knobs). I'm running the Teensy and the motor driver off the same 5V 1A switching power regulator. After running the circuit with the motor spinning for anywhere from a few minutes to a few hours, the Teensy will suddenly get hot, and if left on for long enough after that (a few minutes) will simply die from the heat. But if I feel the Teensy getting hot at the moment it first starts heating up and power down til it cools off, it'll still run (and still be programmable) until it gets hot again after a few minutes and I have to power down again. Once it happens once, the heat continues any time I power it up, even if I put an empty program on it and/or completely remove it from the circuit besides Vin and ground. Also worth noting is that nothing else in the circuit has gotten warm or been damaged in any way.
So here's the one clue I've been able to find: If I measure the current into the Vin pin when I first start testing the circuit and program with a brand new Teensy, the Teensy is only pulling ~20mA total. No matter what I do with the motor driver and I/Os, it stays right around there, where it should. Once it inevitably starts getting hot its suddenly pulling ~4-500mA, even if I completely remove the Teensy from the circuit and only leave power and ground connected. This same thing has happened with a handful of Teensy 3.2s over the past few weeks, the only difference being one damaged one ended up pulling closer to 250mA rather than 4-500mA.
I've been staring at my scope to see if repeatedly starting and stopping the motor is causing a potentially lethal spike in voltage, or a brownout, and it seems to stay good and steady at 5v as far as I can tell even when there's a big spike in current on the motor when being switched on and off.
So I'm having a hard time diagnosing, and I know it would be difficult to impossible to diagnose from afar. Can anyone tell me, does the massive current draw from the Teensy I'm seeing at least point to any specific type of damage? Any other thoughts? Any responses are much appreciated, thank you.
I have a circuit in which a Teensy 3.2 is controlling a motor driver and a few simple digital and analog I/Os (just a few buttons and knobs). I'm running the Teensy and the motor driver off the same 5V 1A switching power regulator. After running the circuit with the motor spinning for anywhere from a few minutes to a few hours, the Teensy will suddenly get hot, and if left on for long enough after that (a few minutes) will simply die from the heat. But if I feel the Teensy getting hot at the moment it first starts heating up and power down til it cools off, it'll still run (and still be programmable) until it gets hot again after a few minutes and I have to power down again. Once it happens once, the heat continues any time I power it up, even if I put an empty program on it and/or completely remove it from the circuit besides Vin and ground. Also worth noting is that nothing else in the circuit has gotten warm or been damaged in any way.
So here's the one clue I've been able to find: If I measure the current into the Vin pin when I first start testing the circuit and program with a brand new Teensy, the Teensy is only pulling ~20mA total. No matter what I do with the motor driver and I/Os, it stays right around there, where it should. Once it inevitably starts getting hot its suddenly pulling ~4-500mA, even if I completely remove the Teensy from the circuit and only leave power and ground connected. This same thing has happened with a handful of Teensy 3.2s over the past few weeks, the only difference being one damaged one ended up pulling closer to 250mA rather than 4-500mA.
I've been staring at my scope to see if repeatedly starting and stopping the motor is causing a potentially lethal spike in voltage, or a brownout, and it seems to stay good and steady at 5v as far as I can tell even when there's a big spike in current on the motor when being switched on and off.
So I'm having a hard time diagnosing, and I know it would be difficult to impossible to diagnose from afar. Can anyone tell me, does the massive current draw from the Teensy I'm seeing at least point to any specific type of damage? Any other thoughts? Any responses are much appreciated, thank you.